OCI client from Oracle distributes un ldap.h which may collision with the SO ldap.h.You can, remove the Oracle ldap.h and build or configure php without oci8 and then add OCI8 later as a shared extension.This latter step is easiest using PECL: pecl install oci8. You will then need to add 'extension=oci8.so' to your php.ini.

If you're running on Windows XP with Apache, and you installed PHP 5 from the windows installer rather than the full zipped version - you may not have the php_ldap.dll file.

I had to follow the steps above, making sure PHP was added to my Windows Path, adding the 2 dll files to the system32 directory, also making sure the php.ini extensions directory was set correctly (in my case: C:\Program Files\PHP\ext).

Still was a getting a message about not being able to locate the "php_lamp.dll" file. I finally went back, downloaded the full .zip file of latest PHP version, and that missing dll file is included there - along with many others.

Running under IIS, I found php_ldap would not load even though d:\php contained libeay32.dll and ssleay32.dll, and d:\php was in the PATH environment variable.

I finally tracked this down to the position of d:\php in the PATH. If d:\php is near the head of the PATH, everything works fine. If d:\php is near the end of the PATH, apparently it gets ignored by IIS (even though it works fine from the command line, e.g., with php -m). Have no idea why this is.

I can confirm Frank's note (made 1 year ago, see below) about requirement of "libsasl.dll" library. I have "PHP Version 5.4.7" and my Apache fails to restart with error saying, that "libsasl.dll" is missing, once I enable php_ldap.dll extension in PHP configuration.

What is even more strange, I DO HAVE this library (along with required "ssleay32.dll" and "libeay32.dll" in my PHP's directory and my PHP's directory IS listed in Windows' PATH variable and even so, I'm facing the problem of Apache failing to start.

The only workaround, I found is to copy "libsasl.dll" to "system32" system directory. Solution, that PHP documentation here discourages.

So, to summarize, section "Note to Win32 users" is twice wrong. You DO have to have "libsasl.dll" directory and you have to place it in your system folder.

Users of the "WAMP Server" software need to enter PHP's path... as the documentation says. Although apache\apache[...]\bin\ also contains the files mentioned, this does not suffice for some reason.For me, the path is C:\wamp\bin\php\php5.5.12